A framed "death towel" fragment from Charles Gunther's collection is labeled:

This is the Blood of "Abraham Lincoln"

Gunther sent the stained relic to the Greater America Exposition in Omaha, Nebraska in 1899 together with the deathbed sheet and a pillow fragment attributed to the Petersen House. (SCHEIDLER 50)

Framed towel fragment allegedly stained with Abraham Lincoln's blood.

Piece of towel used to staunch blood of A. Lincoln. Given to W.S. Kaufman by young Peterson, son of man into whose house Lincoln was taken from theatre in which he was shot.

Dr. Charles Sabin Taft, who attended Lincoln at the Petersen's house, wrote that "clean napkins were laid over the crimson stains on the pillow" whenever Mary Lincoln visited her husband's deathbed. (TAFT)

"Proof" note from the framed towel fragment.

Gone to the Libby Prison Museum

Mr. B.F. Weishampel, of this city, has had in his possession since 1865 a memento of the Lincoln assassination. It consisted of a portion of the towel that was placed under the President's head when dying, the blood stains still being visible. It was framed along with affidavits and a court certificate vouching its genuineness. Mr. Weishampel has recently disposed of it to the manager of the Libby Prison Museum, Chicago, for exhibition in the relic department. (LPWM SCRAPBOOK)

The Boston Transcript described Gunther's acquisition of the death towel in 1890:
Libby Prison War Museum advertising card, c. 1890 (ICHi-30975).
A piece of folded paper behind the death towel is labeled "Proof." Inside is written: